Point I. His own Might.
We ask Him during Advent to stir up His might for four different reasons.
(1) To protect and deliver us. "Stir up Thy might, we beseech Thee O Lord and come: that by Thy protection we may deserve to be delivered from the threatening dangers of our sins and by Thy deliverance be saved." (The "Collect" for Advent Sunday.)
We ask Him to show His might by protecting us from dangers and by delivering us from sin. We want to spend a good Advent, we want to prepare well for His Coming, then there rise up before us the "threatening dangers of our sins"—those old temptations that are sure to come back again as soon as we begin to put forth fresh effort. Are we to be discouraged, to dread them, to say we are sure to fall again, and thus give the enemy a hold over us? No, but to believe that our God Who is coming will protect us in the day of battle, that though to humiliate and to strengthen us, He may still permit the temptations, yet He will Himself be our shield and buckler, and will deliver us if we trust in His strength and not in our own—"Stir up Thy might, O Lord, and come to protect and deliver."
(2) To free us from adversity. "Stir up Thy power, we beseech Thee O Lord and come, that they who confide in Thy mercy may be more speedily freed from all adversity" (The "Collect" for Friday in Ember week).
The adversity from which the Church prays to be freed here is probably the same as she continually teaches us to pray for deliverance from in her Litanies: war, pestilence, famine, floods, earthquakes—all things which damage the peace of nations and the produce of the earth, great national disasters. From all such the world will never be free till the Advent of her Lord, till God stirs up His power and comes to save it. Meanwhile for our consolation we can remember that it is when God's judgments are in the earth that the nations learn justice (Isaias xxvi. 9). Adversity is a great teacher and trainer for Heaven, and as we advance in the spiritual life we see more and more that many things which are adversity to the body are prosperity to the soul. We should naturally like to be freed from the adversity of sickness, poverty, failure, loss of friends, of health and strength, but all these adversities have their work to do. "These are they who came out of great tribulation," and it is probable that but for the tribulation many would never "have washed their robes and have made them white in the blood of the Lamb" (Apoc. vii. 14). Let us strive to be amongst those who trust Him, who confide in His mercy, who believe that He knows what is best for them, and who gladly let Him arrange all for them. He will stir up His power and speedily free them one day, but it will not be till the flail of adversity has done its work and the corn is ready to be garnered in the heavenly barns.
(3) To save us. "Stir up Thy might O Lord and come to save us."
In the Masses for the third week, that is Ember week, the prayer occurs five times, twice in the Mass for the third Sunday and three times in that for Ember Saturday. The time of the birth of the Saviour is drawing nearer, and the Church is beginning to be importunate. Stir up Thy might; for though He is coming as a little helpless infant, He is God "mighty to save."
(4) To accelerate His Coming. "Stir up Thy might, we beseech Thee O Lord and come; and succour us with great power, that by the help of Thy grace, the indulgence of Thy mercy may accelerate what our sins impede." (The "Collect" for the 4th. Sunday of Advent).
We ask Him to stir up His might in coming. His Advents show His Omnipotence. Only a God could come to this world to save it, only a God could come to a soul and raise it to the supernatural state. These are miracles and we ask Him to stir up His might to come and work them. It is our sins that hold Him back and hinder His work both in our own souls and in the world. We want them to do so no more and so we ask for His succour and indulgence.